Three-dimensional integrated circuit structure and method of manufacturing the same

ABSTRACT

Provided is a 3DIC structure includes a wafer, a die and a dielectric layer. The die is over and bonded to the wafer. The dielectric layer is over the wafer and aside the die, covering sidewalls of the die. A total thickness variation (TTV) of the die is less than 0.8 μm.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of U.S. provisionalapplication Ser. No. 62/581,774, filed on Nov. 5, 2017. The entirety ofthe above-mentioned patent application is hereby incorporated byreference herein and made a part of this specification.

BACKGROUND

The semiconductor industry has experienced rapid growth due tocontinuous improvements in the integration density of various electroniccomponents (i.e., transistors, diodes, resistors, capacitors, etc.). Forthe most part, this improvement in integration density has come fromcontinuous reductions in minimum feature size, which allows more of thesmaller components to be integrated into a given area. These smallerelectronic components also demand smaller packages that utilize lessarea than previous packages. Some smaller types of packages forsemiconductor components include quad flat packages (QFPs), pin gridarray (PGA) packages, ball grid array (BGA) packages, flip chips (FC),three-dimensional integrated circuits (3DICs), wafer level packages(WLPs), and package on package (PoP) devices and so on.

3DICs provide improved integration density and other advantages, such asfaster speeds and higher bandwidth, because of the decreased length ofinterconnects between the stacked chips. However, there are quite a fewchallenges to be handled for the technology of 3DICs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A to FIG. 1D are schematic cross-sectional views illustrating amethod of forming a three-dimensional integrated chip (3DIC) structureaccording to some embodiments of the disclosure.

FIG. 2 is an enlarged view of a top corner of a die of athree-dimensional integrated chip (3DIC) structure according to someembodiments of the disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a second feature over or on a first feature in the description thatfollows may include embodiments in which the second and first featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the second and first features,such that the second and first features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath”, “below”, “lower”,“on”, “above”, “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the FIG.s. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe FIG.s. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Other features and processes may also be included. For example, testingstructures may be included to aid in the verification testing of the 3Dpackaging or 3DIC devices. The testing structures may include, forexample, test pads formed in a redistribution layer or on a substratethat allows the testing of the 3D packaging or 3DIC, the use of probesand/or probe cards, and the like. The verification testing may beperformed on intermediate structures as well as the final structure.Additionally, the structures and methods disclosed herein may be used inconjunction with testing methodologies that incorporate intermediateverification of known good dies to increase the yield and decreasecosts.

FIG. 1A to FIG. 1D are schematic cross-sectional views illustrating amethod of forming a three-dimensional integrated chip (3DIC) structureaccording to some embodiments of the disclosure.

Referring to FIG. 1A, a wafer 18 including a plurality of dies 16 a, 16b and 16 c is provided. The dies 16 a, 16 b and 16 c may respectively bean application-specific integrated circuit (ASIC) chip, an analog chip,a sensor chip, a wireless and radio frequency chip, a voltage regulatorchip or a memory chips, for example. The dies 16 a, 16 b and 16 c may bethe same types of dies or the different types of dies. The number of thedies formed in the wafer 18 shown in FIG. 1A is merely for illustration,and the disclosure is not limited thereto. In some embodiments, thewafer 18 includes a plurality of dies arranged in an array, and thenumber of the dies may be adjusted according to design of products. Insome embodiments, the dies 16 a, 16 b and 16 c may be separated after adie-saw process performed on the scribe regions 15.

In some embodiments, the wafer 18 includes a substrate 10, a devicelayer 11, a metallization structure 12, a passivation layer 13 and aplurality of pads 14. The substrate 10 is a semiconductor substrate suchas a silicon substrate. The substrate 10 is, for example, a bulk siliconsubstrate, a doped silicon substrate, an undoped silicon substrate, or asilicon-on-insulator (SOI) substrate. The dopant of the doped siliconsubstrate may be an N-type dopant, a P-type dopant or a combinationthereof. The substrate 10 may also be formed by the other semiconductormaterials. The other semiconductor materials include but are not limitedto silicon germanium, silicon carbide, gallium arsenide, or the like.The substrate 10 includes active areas and isolation structures (notshown).

The device layer 11 includes a wide variety of devices (not shown)formed on the active areas of the substrate 10. In some embodiments, thedevices include active components, passive components, or a combinationthereof. In some embodiments, the devices include integrated circuitdevices, for example. The devices are, for example, transistors,capacitors, resistors, diodes, photodiodes, fuse devices, or othersimilar devices. That is to say, the wafer 18 is a wafer with devicesframed in it, instead of a carrier. The metallization structure 12 isformed over the substrate 10 and the device layer 11. In someembodiments, the metallization structure 12 includes one or moredielectric layers and interconnection structures formed therein (notshown). The interconnection structures include multiple layers ofcontacts, conductive lines and plugs, and are electrically connected tothe devices in the device layer 11. In some embodiments, theinterconnection structures may also be formed in the scribe regions 15.

The pads 14 are formed over the metallization structure 12. The pads 14are electrically connected to the interconnection structure in themetallization structure 12, so as to provide an external connection ofthe devices in the device layer 11. The material of the pads 14 mayinclude metal or metal alloy, such as aluminum, copper, nickel, oralloys thereof. In some embodiments, the pad 14 in the scribe region 15may serve as a mark such as an alignment mark or an overlay mark of atest key structure aside the dies 16 a, 16 b or 16 c.

The passivation layer 13 is formed over metallization structure 12 tocover the sidewalls of the pads 14. The passivation layer 13 may be asingle layer structure or a multilayer structure. In some embodiments,the passivation layer 13 is also referred as a dielectric layer. Thepassivation layer 13 includes an insulating material such as siliconoxide, silicon nitride, low-k dielectric material such as carbon dopedoxides, extremely low-k dielectric material such as porous carbon dopedsilicon dioxide, polymer, or a combination thereof. The polymer is, forinstance, polybenzoxazole (PBO), polyimide, benzocyclobutene (BCB), acombination thereof, or the like. In some embodiments, the top surfaceof the passivation layer 13 is substantially level with the top surfaceof the pads 14. The top surface of the passivation layer 13 and the topsurface of the pads 14 form an active surface of the wafer 18. In someembodiments, the active surface of the wafer 18 is also referred as afirst surface 18 a (or referred as front surface) of the wafer 18. Thebottom surface opposite to the first surface 18 a is a second surface 18b (or referred as back surface) of the wafer 18.

In other words, the die 16 a, 16 b or 16 c respectively includes thesubstrate 10, the device layer 11, the metallization structure 12, thepassivation layer 13, and the pads 14. The pads 14 are electricallyconnected to the integrated circuit devices formed on the substrate 10through the interconnection structure of the metallization structure 12.

Still referring to FIG. 1A, a plurality of dies 19 a, 19 b and 19 c arebonded to the wafer 18 through a bonding structure 28, for example. Insome embodiments, the dies 19 a, 19 b and 19 c respectively include anactive component, or a passive component. In some embodiments, the dies19 a, 19 b and 19 c may respectively be an application-specificintegrated circuit (ASIC) chip, an analog chip, a sensor chip, awireless and radio frequency chip, a voltage regulator chip or a memorychips, for example. The dies 19 a, 19 b, and 19 c may be the same typesof dies or the different types of dies.

In some embodiments, the dies 19 a, 19 b and 19 c respectively includesa substrate 20, a device layer 21, a metallization structure 22, apassivation layer 23 and a plurality of pads 24. In some embodiments,the materials and the structural characteristics of the substrate 20,the device layer 21, the metallization structure 22, the passivationlayer 23 and the pads 24 are similar to or different from those of thesubstrate 10, the device layer 11, the metallization structure 12, thepassivation layer 13 and the pads 14, respectively.

In some embodiments, the dies 19 a, 19 b and 19 c are dies cut from awafer or a plurality of wafers by die-saw processes. That is, the dies19 a, 19 b and 19 c may be cut from a same wafer or different wafers.Before the dies 19 a, 19 b and 19 c are singulated, a polishing processmay be performed for thinning the wafer. Thereafter, the dies 19 a, 19 band 19 c are bonded to the wafer 18.

The dies 19 a, 19 b and 19 c may have the same size or different sizes.In some embodiments in which the dies 19 a, 19 b and 19 c have the samesize, the top surfaces of the dies 19 a, 19 b and 19 c are substantiallylevel with each other. In some embodiments, a plurality of gaps 25 areexisted between the dies 19 a, 19 b, and 19 c. That is to say, the dies19 a, 19 b and 19 c are discretely located on the wafer 18. The width W1of the gap 25, that is, the distance between the adjacent dies 19 a and19 b, or 19 b and 19 c, ranges from 30 μm to 1000 μm.

The dies 19 a, 19 b, and 19 c respectively have a first surface 26 a anda second surface 26 b opposite to each other. In some embodiments, thefirst surface 26 a is an active surface (or referred as a front surface)of the die 19 a, 19 b or 19 c including a surface of the passivationlayer 23 and a surface of the pads 24. The second surface 26 b is alsoreferred as a back surface of the die 19 a, 19 b, or 19 c.

Still referring to FIG. 1A, the bonding structure 28 includes a bondinglayer 17 and a plurality of bonding layers 27. In some embodiments, thebonding layer 17 is formed on the first surface 18 a of the wafer 18.The bonding layers 27 are formed on the first surfaces 26 a of the dies19 a, 19 b and 19 c.

In some embodiments, the bonding layer 17 and the bonding layer 27respectively includes a dielectric material. In some other embodiments,the bonding layer 17 and the bonding layer 27 respectively includes adielectric material and a conductive material embedded in the dielectricmaterial. The materials of the bonding layer 17 and the bonding layers27 may be the same or different. The dielectric material includes oxidesuch as silicon oxide, nitride such as silicon nitride, oxynitride suchas silicon oxynitride, polymer, or a combination thereof. The polymerincludes PBO, polyimide, BCB, a combination thereof, or the like, forexample. The conductive material may include metal, metal alloy, or acombination thereof. In some embodiments, the conductive material is,for instance, copper, nickel, aluminum, tungsten, alloys thereof, or acombination thereof.

In some embodiments in which the bonding layer 17 and 27 include adielectric material, the forming method thereof include a depositionprocess such as a chemical vapor (CVD) deposition process. In someembodiments in which the bonding layer 17 and 27 include a dielectricmaterial and a conductive material, the forming method thereof furtherincludes forming one or more openings in the dielectric material, andthen forming the conductive material in the opening by, for example, aphysical vapor deposition (PVD) process, or a plating process, or thelike. In some embodiments, the surface of the dielectric material andthe surface of the conductive material are substantially coplanar witheach other.

In some embodiments, the dies 19 a, 19 b and 19 c are respectivelyaligned with the dies 16 a, 16 b and 16 c. The bonding layers 27 on thefirst surface 26 a of the dies 19 a, 19 b and 19 c are bonded to thebonding layer 17 on the first surface 18 a of the wafer 18, and form abonding structure 28 between the wafer and the dies 19 a, 19 b and 19 c.In other words, the dies 19 a/19 b/19 c and the wafer 18 are configuredas face to face. In some embodiments, the bonding layers 27 are bondedto the bonding layer 17 by a hybrid bonding process, a fusion bondingprocess, or a combination thereof.

In some embodiments in which the bonding layer 27 and the bonding layer17 include dielectric material, the bonding structure 28 includes afusion bonding. The bonding operation of fusion bonding may be performedas follows. First, to avoid the occurrence of the unbonded areas (i.e.interface bubbles), the to-be-bonded surfaces of the bonding layer 17(that is, the top surface of the bonding layer 17) and the bonding layer27 (that is, the bottom surface of the bonding layer 27) are processedto be sufficiently clean and smooth. Then, the dies 19 a, 19 b, and 19 chaving the bonding layer 27 and the dies 16 a, 16 b and 16 c of thewafer 18 having the bonding layer 17 are aligned and placed in physicalcontact at room temperature with slight pressure to initiate a bondingoperation. Thereafter, an annealing process at elevated temperatures isperformed to strengthen the chemical bonds between the to-be-bondedsurfaces of the bonding layer 17 and the bonding layer 27 and totransform the chemical bonds into covalent bonds.

In some embodiments in which the bonding layer 17 and the bonding layer27 include the dielectric material and the conductive material, thebonding structure 28 includes a hybrid bonding, the hybrid bondinginvolves at least two types of bonding, including metal-to-metal bondingand non-metal-to-non-metal bonding such as dielectric-to-dielectricbonding. That is to say, the conductive material and the conductivematerial are bonded by metal-to-metal bonding, the dielectric materialand the dielectric material are bonded by dielectric-to-dielectricbonding.

In some other embodiments, the dies 19 a, 19 b and 19 c may be bonded tothe wafer 18 without the bonding structure 28 therebetween. The dies 19a, 19 b and 19 c are aligned with the dies 16 a, 16 b and 16 c,respectively. The pads 24 are aligned with the pads 14, the passivationlayers 23 are aligned with the passivation layer 13. Thereafter, thepads 24 and the passivation layers 23 of the dies 19 a, 19 b and 19 care bonded to the pads 14 and the passivation layer 13 of the wafer 18by a suitable bonding method such as a hybrid bonding, a fusion bonding,or a combination thereof.

In some other embodiments, the dies 19 a, 19 b and 19 c may be bonded tothe wafer 18 though a plurality of connectors (not shown), and anunderfill layer may be formed to fill the space between the dies 19 a,19 b, 19 c and the wafer 18, and surround the connectors. The connectorsare located between the pads 14 and the pads 24 to electrically connectthe dies 19 a, 19 b, and 19 c, and the wafer 18. The connector may beconductive bumps such as solder bumps, silver balls, copper balls, goldbumps, copper bumps, copper posts, or any other suitable metallic bumpsor the like.

In some embodiments, as shown in FIG. 1A, one die 19 a, 19 b or 19 c isrespectively bonded to one die 16 a, 16 b or 16 c of the wafer 18, butthe disclosure is not limited thereto. In some other embodiments, two ormore dies may be bonded to one die 16 a, 16 b or 16 c of the wafer 18(not shown).

In some embodiments, after the dies 19 a, 19 b and 19 c are bonded tothe wafer 18, a grinding process is performed for further thinning thedies 19 a, 19 b and 19 c. During the grinding process, the dies 19 a, 19b and 19 c are thinned. In some embodiments, after the grinding processis performed, the height H1 (or referred as thickness) of the die 19 a,19 b or 19 c ranges from 5 μm to 750 μm. In an exemplary embodiment, theheight H1 is 15 μm, for example. The width W0 of the die 19 a, 19 b or19 c ranges from 1 min to 30 mm.

Referring to the enlarged view of the corner α2 of the die 19 a, 19 b or19 c shown in FIG. 1A, in some embodiments, the top corners α1 and α2are slighted damaged and being rounded after the grinding process isperformed.

Referring to FIG. 1B, a dielectric layer 29 is then formed over thewafer 18 and on the dies 19 a, 19 b and 19 c. The dielectric layer 29may be a single layer structure or a multi-layer structure. In someembodiments, the material of the dielectric layer 29 includes aninorganic dielectric material, an organic dielectric material, or acombination thereof. The inorganic dielectric material includes oxidesuch as silicon oxide, nitride such as silicon nitride, oxynitride suchas silicon oxynitride, silicon carbonitride (SiCN), silicon carbon oxide(SiCO), or a combination thereof. The organic dielectric materialincludes polymer such as polybenzoxazole (PBO), polyimide,benzocyclobutene (BCB), epoxy, a combination thereof, or the like. Theforming method of the dielectric layer 29 includes a deposition processsuch as chemical vapor deposition (CVD), plasma-enhanced chemical vapordeposition (PECVD), or the like.

Still referring to FIG. 1B, the dielectric layer 29 covers the secondsurfaces 26 b, the sidewalls of the dies 19 a, 19 b and 19 c, and thesidewalls of the bonding layer 27, and the top surface of the bondinglayer 17. That is to say, the gaps 25 between the dies 19 a, 19 b, and19 c are filled with the dielectric layer 29, and the dielectric layer29 is also referred as a gap-fill dielectric layer.

In some embodiments, the dielectric layer 29 includes a gap fillstructure 31 in the gaps 25 and a plurality of protrusions 30 c on thetops of the dies 19 a, 19 b and 19 c. The gap fill structure 31 includesa first part 30 a and a plurality of second parts 30 c, and theprotrusion 30 c is a third part 30 c. Specifically, the dielectric layer29 includes the first part 30 a, the second parts 30 b and the thirdparts 30 c from bottom to top. The first part 30 a and the second parts30 b are located in the gaps 25 between the dies 19 a, 19 b and 19 c, soas to surround and cover sidewalls of the dies 19 a, 19 b and 19 c. Thethird parts 30 c (or referred as protrusions 30 c) are located on thedies 19 a, 19 c and 19 c and the second parts 30 b, so as to cover thetop surfaces of the dies 19 a, 19 b and 19 c. The details are describedas below.

The first part 30 a is located on the bonding layer 17 and in the gaps25. The width W2 of the first part 30 a is substantially the same as thewidth W1 of the gap 25. In some embodiments, the top surface of thefirst part 30 a is lower than the second surface 26 b of the die 19 a,19 b or 19 c. That is to say, the top surface of the dielectric layer 29between the dies 19 a, 19 b and 19 c is lower than the second surfaces26 b of the dies 19 a, 19 b and 19 c. In some embodiments, the thicknessT1 of the first part 30 a ranges from 5 μm to 750 μm. In someembodiments, the height difference H3 between the second surface 26 b ofthe die 19 a, 19 b or 19 c and the top surface of the first part 30 a(that is, the height of second part 30 b) ranges from 0.1 μm to 740 μm.

The second parts 30 b are located on the first part 30 a and cover upperportions of the sidewalls of the die 19 a, 19 b or 19 c. Specifically,in some embodiments, the second parts 30 b are located on the edge ofthe first part, surrounding and covering upper portions of sidewalls ofthe dies 19 a, 19 b and 19 c. The second parts 30 b at least cover aportion of the top surface of the first part 30 a. The top surfaces ofthe second parts 30 b are level with the second surfaces 26 b of thedies 19 a, 19 b and 19 c. In some embodiments, the width W3 of thesecond part 30 b ranges from 15 μm to 500 μm. In some embodiments, theratio of the width W3 to the width W2 ranges from 0.015 to 0.5. That isto say, in some embodiments, the gap 25 may be filled up with thedielectric layer 29.

The first part 30 a and the second part 30 b form the gap fill structure31 located in the gaps 25. In some embodiments, the cross-section shapeof the gap fill structure 31 may be square, rectangle, or U-shaped, butthe disclosure is not limited thereto. In some embodiments in which thecross-section shape of the gap fill structure 31 is U-shaped, the gapfill structure 31 has a recess 32 on the first part 30 a and between thesecond parts 30 b. The bottom surface of the recess 32 is the topsurface of the first part 30 a. The sidewall of the recess 32 is formedof the sidewall of the second part 30 b. The recess 32 is within the gap25, and the depth of the recess 32 equals to the height difference H3 orthe height of the second part 30 b. That is to say, in some embodiments,the gap 25 is mostly filled with the dielectric layer 29, except anupper portion of the gap 25 is not filled with the dielectric layer 29.

The third parts 30 c are located on the dies 19 a, 19 b and 19 c and thesecond parts 30 b, covering the second surfaces 26 b of the dies 19 a,19 b and 19 c and the second parts 30 b. The width of the third part 30c is larger than the width W0 of the die 19 a, 19 b or 19 c. In someembodiments, the value of the difference between the width of the thirdpart 30 c and the width W0 of the die 19 a, 19 b or 19 c equals to thesum of the widths (W3*2) of the second parts 30 b on opposite sidewallsof the die 19 a, 19 b or 19 c.

Referring to the enlarged view of the top corner α2 of the die 19 a, 19b or 19 c, the top cornerα2 are covered by the dielectric layer 29.

Referring to FIG. 1B and FIG. 1C, a portion of the dielectric layer 29is removed, such that the second surfaces 26 b of the die 19 a, 19 b and19 c are exposed. The removal method includes a first planarizationprocess such as a chemical mechanical polishing (CMP) process. Theslurry used in the planarization process may have a high selectivityratio of the dielectric layer 29 to the substrate 20 of the die 19 a, 19b or 19 c. In some embodiments, the selectivity ratio of the dielectriclayer 29 to the substrate 20 is greater than 4. In some embodiments, theselectivity ratio ranges from 1 to 100. In some embodiments, thepolishing rate of the first planarization process ranges from 0.5 μm/minto 3 μm/min.

In some embodiments, as shown in the dotted line in FIG. 1C, the thirdparts 30 c of the dielectric layer 29 are removed, and the gap fillstructure 31 of the dielectric layer 29 is not removed during the firstplanarization process, and the gap fill structure 31 remained form adielectric layer 29 a.

Referring to FIG. 1B and FIG. 1C, in some other embodiments, the thirdparts 30 c and a portion of the gap fill structure 31 of the dielectriclayer 29 are removed during the first planarization process, and adielectric layer 29 a including a gap fill structure 31 a is formed, andthe gap fill structure 31 a has a recess 32 a.

In some embodiments, the size of the recess 32 a is slightly larger thanthe size of the recess 32. Herein, the term “size” refers to width ordepth, or a combination thereof. In some embodiments, the recess 32 a iswider and deeper than the recess 32. That is to say, a portion of thefirst part 30 a and portions of the second parts 30 b are removed duringthe planarization process, and a first part 30 d and a second part 30 eare remained to form the dielectric layer 29 a (the gap fill structure31 a). In some embodiments, the thickness T2 of the first part 30 d isless than the thickness T1 of the first part 30 a (shown in FIG. 1B).That is, the height difference H4 between the second surface 26 b of thedie 19 a, 19 b or 19 c and the top surface of the first part 30 e isgreater than the height difference H3 (shown in FIG. 1B).

Still referring to FIG. 1B and FIG. 1C, in some embodiments, the secondpart 30 e is thinner and higher than the second part 30 b. The width W4of the second part 30 e is less than the width W3 of the second part 30b (shown in FIG. 1B). The height of the second part 30 e (equals to theheight difference H4) is larger than the height of the second part 30 b(equals to the height difference H3). In some embodiments, the topsurface of the second part 30 e (that is, the top surface of thedielectric layer 29 a) is coplanar with the second surfaces 26 b of thedies 19 a, 19 b and 19 c.

Referring to the enlarged view of the top corners α1 and α2 showing inFIG. 1C, after the planarization process, the rounded part of the topcorners α1 and α2 are still covered by the dielectric layer 29 a, andthe top surface of the dielectric layer 29 a is coplanar with the secondsurfaces 26 b of the dies 19 a, 19 b and 19 c.

Referring to FIG. 1C and FIG. 1D, a portion of the dielectric layer 29 aand portions of the dies 19 a, 19 b and 19 c are removed, such that adielectric layer 29 b is formed, and the height of the die 19 a, 19 b or19 c is reduced from H1 to H2. In some embodiments, the height H2 rangesfrom 4 μm to 749 μm. In the exemplary embodiment in which the height H1is 15 μm, the height H2 is 10 μm. The removal method includes a secondplanarization process, such as a CMP process. The slurry used in theplanarization process may have a high selectivity ratio of the substrate20 of the die 19 a, 19 b or 19 c to the dielectric layer 29 a. In someembodiments, the selectivity ratio ranges from 1 to 10. In someembodiments, the polishing rate of the second planarization processranges from 0.4 gm/min to 1.5 μm/min. Referring to FIG. 1D, thedielectric layer 29 b is over the wafer 18 and aside the dies 19 a, 19 band 19 c to cover the sidewalls of the dies 19 a, 19 b and 19 c. In someembodiments, the top surface of the dielectric layer 29 b issubstantially coplanar with the second surfaces 26 b of the dies 19 a,19 b and 19 c. A 3DIC structure 100 is thus completed.

Still referring to FIG. 1D, the dies 19 a, 19 b and 19 c respectivelyhas a top corner β1 and a top corner β2 opposite to each other. In someembodiments, the rounded part the top corners α1 and α2 are completedremoved during the planarization process, and the top corners β1 and β2are right angle, that is, equal to 90°. In some embodiments, most of therounded part of the top corners α1 and α2 are removed, and a tinyportion of the rounded part is remained in top corners β1 and β2. Insome embodiments, the top corner β1 and the top corner β2 aresymmetrical or asymmetrical.

FIG. 2 is an enlarged view of the top corner β2, for the sake ofbrevity, one top corner is shown in FIG. 2. Referring to FIG. 2, the topcorner β2 includes a rounded part 35. The rounded part 35 connects tothe sidewall 36 and the second surface 26 b of the die 19 a, 19 b or 19c. The sidewall 36 and the rounded part 35 are covered by the dielectriclayer 29 b. In some embodiment, an included angle θ between the roundedpart 35 and an extension of the sidewall of the die 19 a, 19 b or 19 c(shown in dotted line) is less than 15°. In some embodiments in whichthe top corner β2 is a right angle, the included angle θ is 0°. That isto say, the included angle θ is greater than or equal to 0°, and lessthan 15°.

Still referring to FIG. 2, in some embodiments, a total thicknessvariation TTV of the die 19 a, 19 b or 19 c is greater than or equal to0 μm, and less than 0.8 μm. The width W10 of the rounded part is greaterthan or equal to 0 μm, and less than 50 μm. The farther away from thesidewall of the die, the smaller the thickness variation of the rounderpart. In some embodiments, a total thickness variation within wafer isless than 50 μm.

In some embodiments of the disclosure, after the 3DIC structure isformed, subsequent processes may be performed to stack more layers ofdies or devices on the 3DIC structure, so as to form a multi-layerstacked chip-on-wafer structure. Vias such as through silicon vias(TSVs), through insulator vias (TIVs), through dielectric vias (TDVs),or the like, or a combination thereof may be formed to electricalconnect the dies or devices on the 3DIC structure to the dies 19 a/19b/19 c and the wafer 18. In some embodiments, after the multi-layerstacked chip-on-wafer structure is formed, a die saw process isperformed to singulate the stacked structure.

In the embodiments of the disclosure, the dies 19 a, 19 b and 19 c arethinned during the grinding process and the second planarizationprocess. During the grinding process, a great amount of the die 19 a/19b/19 c is removed, and the die 19 a/19 b/19 c is greatly thinned. Duringthe second planarization process, a small amount of the die 19 a/19 b/19c is removed, and the die 19 a/19 b/19 c is slighted thinned. That is tosay, the thickness of the die 19 a/19 b/19 c reduced in the grindingprocess is much greater than that in the second planarization process.

On the other hand, between the grinding process and the step of formingthe dielectric layer, no planarization process is performed in someembodiments. Both the first and the second planarization process areperformed after the dielectric layer is formed. Therefore, the topcorners of the die are covered and protected by the dielectric layerduring the first and the second planarization processes. During thesecond planarization process, the top corner is covered by thedielectric layer, and the slurry used in the second planarizationprocess has a high selectivity ratio of the substrate of the die to thedielectric layer, therefore, the dielectric layer on the top corner mayprotect and be used as a hard mask of the top corner of the die. As aresult, after the first and second planarization process is performed,the rounding issue may occurred during the grinding process is reducedor eliminated. The TTV of the die is also reduced.

In accordance with some embodiments of the disclosure, a method ofmanufacturing a three-dimensional integrated circuit (3DIC) structureincludes the following steps. A die is bonded to a wafer. A dielectriclayer is formed on the wafer and the die, so as to cover a top surface,top corners and sidewalls of the die. A portion of the dielectric layercovering the top surface of the die is removed. A portion of the die andanother portion of the dielectric layer are removed.

In accordance with alternative embodiments of the disclosure, a methodof manufacturing a 3DIC structure includes the following steps. Aplurality of dies are bonded to a wafer. A dielectric layer is formed onthe wafer and the dies, so as to cover top surfaces and sidewalls of thedies, wherein a top surface of the dielectric layer between the dies islower than top surfaces of the dies. A first planarization process isperformed to remove a portion of the dielectric layer, so as to exposethe top surfaces of the dies. A second planarization process isperformed to remove another portion of the dielectric layer and portionsof the dies. Top corners of the dies are covered by the dielectric layerduring the first planarization process and the second planarizationprocess.

In accordance with some embodiments of the disclosure, a 3DIC structureincludes a wafer, a die and a dielectric layer. The die is over andbonded to the wafer. The dielectric layer is over the wafer and asidethe die, covering sidewalls of the die. A total thickness variation(TTV) of the die is less than 0.8 μm.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the disclosure.Those skilled in the art should appreciate that they may readily use thedisclosure as a basis for designing or modifying other processes andstructures for carrying out the same purposes and/or achieving the sameadvantages of the embodiments introduced herein. Those skilled in theart should also realize that such equivalent constructions do not departfrom the spirit and scope of the disclosure, and that they may makevarious changes, substitutions, and alterations herein without departingfrom the spirit and scope of the disclosure.

What is claimed is:
 1. A method of manufacturing a three-dimensionalintegrated circuit (3DIC) structure, comprising: bonding a die to awafer, wherein the die has a first total thickness variation (TTV);forming a dielectric layer on the wafer and the die, so as to cover atop surface, top corners and sidewalls of the die, wherein thedielectric layer comprises a gap fill structure and a protrusionconnected to each other, the gap fill structure is laterally aside thedie to cover the sidewalls of the die, and the protrusion is located onthe die to cover the top surface of the die and a portion of the gapfill structure, wherein the gap fill structure has a recess, and abottom surface of the recess is a top surface of the gap fill structure,and is lower than the top surface of the die; removing a portion of thedielectric layer covering the top surface of the die; and removing aportion of the die and another portion of the dielectric layer, whereinafter the portion of the die is removed, the die has a second TTV, andthe second TTV is less than the first TTV.
 2. The method of claim 1,wherein the die is bonded to the wafer though a bonding structure. 3.The method of claim 2, wherein removing the portion of the die comprisesremoving portions of the top corners of the die.
 4. The method of claim1, wherein the portion of the dielectric layer covering the top surfaceof the die is removed by a first planarization process, the firstplanarization process comprises a first CMP process.
 5. The method ofclaim 4, wherein the portion of the die and another portion of thedielectric layer is removed by a second planarization process, and thesecond planarization process comprises a second CMP process.
 6. Themethod of claim 5, wherein the top corners of the die are covered andprotected by the dielectric layer during the first planarizationprocess.
 7. The method of claim 6, wherein after the secondplanarization process is performed, a top surface of the dielectriclayer is substantially level with a top surface of the die.
 8. Themethod of claim 5, wherein the top corners of the die are laterallycovered and protected by the dielectric layer during the secondplanarization process.
 9. The method of claim 8, wherein the firstplanarization process uses a slurry having a selectivity ratio of thedielectric layer to a substrate of the die, and the selectivity ratioranges from 1 to
 100. 10. The method of claim 8, wherein the secondplanarization process uses a slurry having a selectivity ratio of asubstrate of the die to the dielectric layer, and the selectivity ratioranges from 1 to
 10. 11. A method of manufacturing a 3DIC structure,comprising: bonding a plurality of dies to a wafer; forming a dielectriclayer on the wafer and the dies, covering top surfaces and sidewalls ofthe dies, wherein a top surface of the dielectric layer between the diesis lower than the top surfaces of the dies, wherein the dielectric layercomprises: a gap fill structure, located in gaps between the dies tocover the sidewalls of the dies, wherein the gap fill structure has arecess, and a bottom surface of the recess is the top surface of thedielectric layer between the dies; and a plurality of protrusionsconnecting to the gap fill structure, wherein the plurality of theprotrusions are respectively located on the plurality of the dies, andcover the top surfaces of the plurality of the dies and a portion of thegap fill structure; performing a first planarization process to remove aportion of the dielectric layer, so as to expose the top surfaces of thedies; and performing a second planarization process to remove anotherportion of the dielectric layer and portions of the dies, wherein topcorners of the dies are covered by the dielectric layer during the firstplanarization process, and rounded parts of the top corners of the diesare removed by the second planarization process.
 12. The method of claim11, wherein the plurality of the protrusions are removed by the firstplanarization process.
 13. The method of claim 12, wherein a portion ofthe gap fill structure is removed by the second planarization process.14. The method of claim 12, wherein a portion of the gap fill structureis further removed by the first planarization process.
 15. The method ofclaim 14, wherein another portion of the gap fill structure is removedby the second planarization process.
 16. A method of manufacturing athree-dimensional integrated circuit (3DIC) structure, comprising:bonding a die to a wafer, wherein the die comprises a top corner havinga rounded part; forming a dielectric layer on the wafer and the die, soas to cover a top surface, the top corner and sidewalls of the die,wherein the dielectric layer comprises a gap fill structure and aprotrusion connected to each other, the gap fill structure is laterallyaside the die to cover the sidewalls of the die, and the protrusion islocated on the die to cover the top surface of the die and a portion ofthe gap fill structure, wherein a top surface of the gap fill structureis lower than the top surface of the die; performing a first removalprocess to remove the protrusion of the dielectric layer; and performinga second removal process to remove a portion of the die and a portion ofthe gap fill structure of the dielectric layer, wherein the rounded partof the top corner of the die is removed by the second removal process,and after the performing the second removal process, a total thicknessvariation of the die is reduced.
 17. The method of claim 16, whereinafter the performing the second removal process, the total thicknessvariation of the die is less than 0.8 μm.
 18. The method of claim 16,wherein the first removal process further removes a portion of the gapfill structure.
 19. The method of claim 16, further comprisingperforming a grinding process after the bonding the die to the wafer andbefore the forming the dielectric layer to thin the die.
 20. The methodof claim 19, wherein the rounded part of the top corner is formed duringthe grinding process.